calcareous ooze sample in the protection of the foraminifera tests 

 against crushing. 



It is significant to compare the behavior of the artificial 

 calcareous ooze sample with that of a typical terrestrial sand 

 (quartz grains). Similar 1 -D consolidation tests on quartz sand 

 indicate the initiation of grain crushing at 14,000 to 21,000 kPa 

 (2,000 to 3,000 psl) (Reference 38, pp. 297, 302), versus 50 to 

 200 kPa for the calcareous test grains. 



SHEAR CHARACTERISTICS 



Effective-stress shear strength properties were developed 

 from the results of three triaxial shear tests in which the specimens 

 were consolidated isotropically and then sheared undrained (CIU tests) . 

 A brief review of the triaxial test, with terminology defined, 

 is given in the Appendix. 



Equipment and Procedure Description 



Triaxial shear tests were conducted in conventional equipment 

 (similar to that described in Reference 40) on calcareous ooze 

 specimens 36 mm diameter by 90 mm high (1.4 in. by 3.5 in.). The 

 first shear test, on that specimen consolidated to 37.9 kPa (5.49 

 psi) , used a load ram bushing/seal consisting of two stainless 

 steel linear ball bushings and an 0-ring seal [41], which prevented 

 leakage of cell fluid and proved adequate in minimizing friction 

 on the loading ram. Subsequent shear tests have made use of a new 

 load ram bushing/seal, incorporating a compressed air seal, developed 

 at the University of California at Berkeley, which has demonstrated 

 lower ram friction and has yielded smoother and more consistent 

 data curves. 



Triaxial specimens cut from the tubes of Box Core 4 were of 

 sufficient strength to support themselves during the trimming and 

 cell assembly process. The samples were provided with filter paper 

 side drains (Reference 40, p. 81) and were enclosed in two rubber 

 membranes separated by silicone grease (Reference 40, p. 39). Tap 

 water was used for the cell fluid and salt water for the specimen 

 pore fluid lines, with the salt water system isolated from the 

 mercury pot system by an oil interface. Cell pressures of about 

 345 kPa (50 psi) were used throughout, and consolidation pressures 

 were applied by lowering the specimen pressure via the self-compensating 

 mercury control differential pressure system (Reference 40, p. 

 45-52) . Axial loads were applied with a loading frame moving at 

 a constant rate of strain and through a proving ring; the strain 

 rate was such that 20 percent axial strain was completed in about 

 5-1/2 hours. 



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